Milwaukee MX4 4-Cutter SDS-PLUS Drill Bits

Milwaukee’s MX4 SDS-PLUS drill bits deliver 5x longer life in rebar-embedded concrete through German-engineered 4-cutter solid carbide technology. That’s the headline. The 4-cutter geometry prevents lock-up in rebar, reducing downtime — the main pain point these bits solve.

Skip these if you’re drilling wood or standard masonry without rebar. Standard 2-cutter bits cost less and work fine for basic concrete. But for contractors hitting rebar regularly, the MX4 pays for itself through reduced bit replacement and fewer work stoppages.

4-Cutter Performance in Reinforced Concrete

The enhanced rebar guards and 4-cutter 90° head design provide increased life and durability in hard aggregate and rebar. Most SDS bits use a 2-cutter design that binds when it hits rebar. Milwaukee’s 4-cutter geometry slices through instead of grabbing.

Sharp centering tip reduces bit walking and improves accuracy in concrete and metal decking. That matters when you’re setting anchors or drilling precise holes for electrical and plumbing runs. Breaker points pulverize the material more effectively resulting in faster drilling speeds.

The real innovation is the variable flute design. Variable flutes provide up to 20% more holes per battery charge by removing dust faster and reducing heat. Better dust evacuation means cooler running, which preserves the carbide edge and extends battery life on cordless tools.

Model Configurations

Milwaukee offers two main MX4 kits:

Standard 6-Piece Set (48-20-7499)

• 5/32” x 4” x 6”
• 3/16” x 4” x 6”
• 1/4” x 4” x 6”
• 5/16” x 4” x 6”
• 3/8” x 4” x 6”
• 1/2” x 4” x 6”

This covers most anchor-setting needs from 1/4” to 1/2” — the workhorse sizes for electrical and mechanical contractors.

Chisel and Bit Kit (48-20-7662)

• 5/32” x 4” x 6” MX4 4-Cutter Bit
• 3/16” x 4” x 6” MX4 4-Cutter Bit
• 1/4” x 4” x 6” MX4 4-Cutter Bit
• 3/8” x 4” x 6” MX4 4-Cutter Bit
• 5-1/2” SDS-PLUS Flat Chisel
• 5-1/2” SDS-PLUS Bull-Point Chisel

The chisel kit makes sense if you’re doing demo work alongside drilling. Same quality carbide in the chisels.

Individual bits are also available. The 1” x 8” x 10” bit (48-20-7240) runs heavier duty applications. Montana contractors drilling for seismic retrofits or heavy equipment anchors need these larger diameters.

Key Specifications

Feature	Specification
Shank Type	SDS-PLUS
Head Material	Solid Carbide
Cutter Design	4-Cutter (4-CT)
Manufacturing	Germany
Wear Indicator	ANSI wear-mark indicator
Certification	Meets ANSI B212.15 standard

The wear mark indicator shows when the bits no longer meet ANSI diameter requirements for proper anchor installation. Critical for structural work where undersized holes compromise holding power.

Who Should Buy MX4 Bits

Worth it for:

• Electrical contractors setting anchors in concrete decks
• Mechanical contractors drilling through reinforced slabs
• Seismic retrofit crews hitting rebar constantly
• Anyone drilling Montana’s high-strength commercial concrete

Skip them for:

• Basic masonry without rebar
• Residential work in standard concrete
• Wood frame construction
• Jobs where 2-cutter bits work fine

The MX4 4-cutter drill bit line provides the ideal solution in general concrete and reinforced concrete for cordless and corded rotary hammer users. At 5x the life in rebar, they’re not cheap bits pretending to be premium — they’re engineered for specific problems that cost real money on jobsites.

FAQ

Are MX4 bits compatible with all SDS-PLUS rotary hammers? Yes, they’re compatible with all SDS-PLUS shank rotary hammer drills. Standard click-in installation.

What’s the actual warranty on MX4 bits? Milwaukee typically offers a limited warranty on accessories, though specific duration wasn’t detailed beyond 30-day returns at select retailers. Contact Milwaukee directly for warranty claims.

Do MX4 bits really deliver 20% more holes per charge? Variable flutes provide up to 20% more holes per battery charge by removing dust faster and reducing heat. Your results depend on concrete hardness and drilling technique.

What makes German manufacturing matter for drill bits? The bits are manufactured in Germany, where carbide tooling expertise runs deep. German carbide formulation and heat treatment consistently outperform bits made elsewhere.

Can MX4 bits drill metal decking? Yes, the sharp centering tip reduces bit walking and improves accuracy in concrete and metal decking. Start slow to prevent walking on smooth metal surfaces.